1. Department of Gastroenterology Isshi Gastro‐Intestinal Clinic 2‐15‐21, Shinozaki‐cho Edogawa‐Ku 133‐0061 Tokyo Japan
2. Department of Endoscopy The Jikei University School of Medicine 3‐15‐8, Nishishinbashi Minato‐Ku 105‐8461 Tokyo Japan
3. Department of Gastroenterology NTT Medical Center Tokyo 5‐9‐22, Higashi‐Gotanda Shinagawa‐Ku 144‐8625 Tokyo Japan
4. Department of Gastroenterology Gamagori City Hospital 1‐1, Mukaida Hirata‐cho Gamagori 443‐8501 Aichi Japan
5. Second Department of Internal Medicine Osaka Medical College 2‐7, Daigakumachi Takatsuki 569‐8686 Osaka Japan
6. Department of Gastroenterology Nippon Medical School Graduate School of Medicine 1‐1‐5, Sendagi Bunkyo‐Ku 133‐8603 Tokyo Japan
7. Department of Medical Innovation Nagoya City University Graduate School Medical Sciences 1, Kwasumi Mizuhocho, Mizuho‐Ku Nagoya 467‐8601 Aichi Japan
8. Division of Endoscopy and Ultrasonography, Department of Laboratory Medicine Kawasaki Medical School 2‐6‐1, Nakasange, Kita‐Ku Okayama 700‐8505 Okayama Japan
9. Division of Gastroenterology and Hepatology, Department of Internal Medicine Katsushika Medical Center, The Jikei University School of Medicine 6‐41‐2, Aoto Katsushika‐Ku 125‐8506 Tokyo Japan
10. Department of General Internal Medicine 2 Kawasaki Medical School Kawasaki Hospital 577, Matsushima Kurashiki 701‐0192 Okayama Japan
11. Department of Laboratory Medicine The Jikei University School of Medicine 3‐25‐8, Nishishinbashi Minato‐Ku 105‐8461 Tokyo Japan